Pulverizing apparatus with oversize recirculation



March 26, 1963 c. D. PARTEN PULVERIZING APPARATUS WITH OVERSIZE RECIRCULATION 4 Sheets-Sheet 1 Filed Jan. 28, 1959 INVENTOR. @WZ flfiriew March 26, 1963 c. n. PARTEN 3,082,962

PULVERIZING APPARATUS WITH OVERSIZE RECIRCULATION Filed Jan. 28. 1959 4 Sheets-Sheet 2 INVENTOR.

i 547 524 42 BY ax? 4 22; i

March 26, 1963 c. D. PARTEN 3,0

PULVERIZING APPARATUS wmx ovERsIzE RECIRCULATION Filed Jan. 28. 1959 4 Sheets-Sheet s March 26, 1963 c. D. PARTEN 3,

PULVERIZING APPARATUS WITH OVERSIZE RECIRCULATION Filed Jan. 28. 1959 4 Sheets-Sheet 4 INVENTOR.

3,982,962 l atented Mar. 26, 1963 3,682,962 PULVERiZlNG APPARATUS WITH OVERSIZE RECHRCULATIGN Carl D. Parten, Minneapolis, Minn assignor to iarten Machinery Company, Minneapoiis, Mind, :1 corporation of Minnesota Filed Ilan. 28, 1959, Ser. No. 7852554 '7 Claims. (Cl. 24152) The present invention relates to a novel grinding or pulverizing apparatus, and more particularly to a novel so-called air-swept type grinder or pulverizer wherein the material to be processed is carried through the apparatus with a flowing stream of gas or air.

An apparatus of the type contemplated herein is capable of grinding or pulverizing a material to provide a fine powder. Frequently, it is desirable to obtain an end product which includes two or more powdered materials mixed together, but difficulties arise with respect to obtainin a substantially uniform mixture or blend of the various powdered materials. It is, therefore, one important object of the present invention to provide a novel pulverizing or grinding apparatus for simultaneously processing a plurality of materials in a manner so that such materials are substantially uniformly blended or mixed together.

It will be appreciated that certain materials to be ground or pulverized can be damaged by the heat created during the grinding operation, and it is, therefore, another object of the present invention to provide a novel apparatus which is constructed for more efiiciently cooling the material during the grinding operation so as to reduce any possibility of injury to the material as a result of overheating.

Still another object of the present invention is to provide a novel grinding or pulverizing apparatus which is constructed for more effectively classifying pulverized material particles as to size and for recirculating larger particles for regrinding.

A further object of the present invention is to provide a novel grinding or pulverizing apparatus having pulverizing rotor means and fan blade means at an end thereof for moving air through the apparatus, which apparatus is constructed so as to support the rotor means at opposite ends thereof.

Still another object of the present invention is to provide a novel grinding or pulverizing apparatus of the type described above having a fan housing over the fan blade means, which fan housing is hingedly supported so as to facilitate access to the interior of the apparatus for maintenance or any other desired purpose.

Other objects and advantages of the present invention will become apparent from the following description and the accompanying drawings wherein:

. FIG. 1 is a perspective view showing an apparatus incorporating features of the present invention;

FIG. 2 is an enlarged fragmentary sectional view taken along line 22 in FIG. 1;

FIG. 3 is a partial substantially vertical and longitudinal sectional view of the apparatus shown in FIG. 1;

FIG. 4 is an enlarged fragmentary cross sectional view taken along line 44 in FIG. 3;

FIG. 5 is a fragmentary sectional view taken along line 5-5 in FIG. 4;

FIG. 6 is a fragmentary sectional view taken along line 66 in FIG. 4;

FIG. 7 is a view showing several of the parts of the grinding apparatus rotor axially offset from each other for purposes of illustration;

FIG. 8 is a left hand end view of the apparatus as viewed in FIG. 1;

FIG. 9 is an enlarged fragmentary partial sectional View taken along line 99 in FIG. 8;

FIG. 10 is an enlarged fragmentary cross sectional view taken along line 10-10 in FIG. 3; and

FIG. 11 is an enlarged fragmentary sectional view taken along line 11-11 in FIG. 8.

Referring now more specifically to the drawings wherein like parts are designated by the same numerals throughout the various figures, an apparatus 20 incorporating features of the present invention is shown best in FIGS. 1 and 3 and is provided with grinding or pulverizing chamber means 22 supported on a suitable base structure 24. An assembly generally designated by the numeral 26 is supported above the base means by a suitable frame structure 28 for feeding one or more ingredients to the pulverizing or grinding means 22, and fan means 30 is associated with the pulverizing or grinding means 22 for drawing air or gas therethrough, which air or gas is utilized for directing pulverizing material to a desired point of discharge.

The pulverizing or grinding means 22 comprises a housing having a cylindrical outer wall 32 and an end wall 34 having an ingredient inlet opening 36 therethrough. A grinding or pulverizing rotor generally designated with the numeral 38 is provided, which rotor has an elongated shaft 4t? extending through a suitable opening in the end wall 34 and rotatably supported by bearings 42 and 44 mounted on the base means 24. The rotor shaft is driven by any suitable means such as an electric motor 46 having a drive pulley 48 fixed on its output shaft, which drive pulley is connected with a pulley 50* on the rotor shaft 40 by belt means 52. The rotor means is provided with a plurality of beater plates 54, 56 and 58 fixed on the shaft 40 within the housing walls 32 and 34. The beater plates which are preferably imperforate respectively carry sets of peripheral circumferentially spaced beater blocks or blades 68, 62 and 64 and also sets of blades or beater blocks 66, 68 and 70 at opposite sides thereof. In addition, the beater plate 54 has an annular series of spaced blade or block members 72 fixed on its side facing the end wall 34 and spaced radially inwardly from the peripheral blocks.

Liner members 74 and 76 are disposed within the cylindrical housing portion 32 and an annular liner member '78 is disposed against the inner surface of the housing end wall 34, which liner members respectively have inner ribs or corrugations 80, 82 and 84 as shown best in FIGS. 4 and 5 for cooperation with the beater blades or blocks to grind and pulverize material passing through the apparatus.

As will be understood, the material enters the milling chamber through the opening 36 with a flowing stream of air or gas and is directed radially outwardly between the beater plate 54 and the liner member 78. The partially ground material then passes around the beater plate 54 and between the beater plates 54 and 56 and then around the beater plate 56. As the beating or pulverizing action progresses, a circulating swirling motion is imparted to the air or gas and material entrained therein so that the larger particles gravitate toward the liner member 76. In order to obtain further pulverizing or grinding action on these particles, a reclassifier or bathe ring 86 is provided between the liner member 74 and 76 for directing the material radially inwardly so that it will be acted upon by the elements carried by the beater plate 58.

Considerable heat will be generated by the grinding process as the material flows around the beater plates, and cooling means is provided for preventing overheating and injury to the material. In accordance with a feature of the present invention, more efiicient cooling is obtained by forming channels in the liner members 74, 76 and 78 so that the liner members cooperate with the housing portions 32 and 34 to provide fluid coolant passageways 88, 90 and 92 as shown in FIGS. 3, 4, and 6. It is important to note that with this arrangement the coolant is in direct contact with the liner members so that the most effective cooling of these liner members and, thus, the material being ground adjacent to and contacting the liner members is obtained. i

The liner members 74 and 76 must fit within the cylindrical housing 32 snugly in order to prevent coolant from leaking from the passageways 88 and 99. This is accomplished easily and relatively economically in accordance with the present invention by splitting the liner members 74 and 76 and by providing them with beveled ends between which wedging blocks 98 and 160 are forced. As shown in FIGS. 4 and 6, the wedge members are respectively secured to studs 102 and 104 which extend outwardly through bushings 106 and 108 mounted in the housing wall 32. Nut members 110 and 112 are threaded onto the outer ends of the studs for drawing the wedge members firmly against the beveled ends of the liner members or rings so as to expand the rings into aggressive engagement with the interior surface of the cylindrical wall 32. Strips 114 and 116 of resilient sealing material are provided between the wedging blocks 98 and 100, respectively, and the outer wall 32 for interrupting the fluid passageways 88 and 91 As shown in FIGS. 1 and 4 a conduit 118 is connected with the cylindrical housing wall 32 and communicates with both of the passageways 88 and 90 for directing liquid coolant to the passageways at one side of the strips 14 and 16, and a drain conduit 120 communicates with these passageways at the opposite sides of the strips. Similar strip means 122 (see FIG. 4) is provided for interrupting the passageway 99, and branch fluid inlet and outlet conduits 124 and 126 are connected with the passageway 90 at opposite sides of the strip 122. It will be appreciated thatthe fluid inlet conduit 118 will be connected to any suitable source of coolant such, for example, as water.

In addition to the above mentioned beater plates, the rotor includes a perforated mill plate 128 having a plurality of small apertures 130 of predetermined size therethrough. Properly ground or pulverized material is carried by an air stream through the apertures 130 while relatively large particles of the material are retarded and gravitate toward the periphery of the mill plate for recirculation in the manner described below.

v The rotor shaft extends from the mill plate through an 144 are secured to the cone plate for directing the larger particles so that they may be recirculated in the manner described below.

The cone plate also carries a plurality of centrifugal fan blades 146 which are disposed within a housing 148 of the fan means 30. As shown in FIG. 8, the housing has an outlet 150 which may be connected to suitable duct means, not shown, for directing the pulverized material to a suitable point of discharge or to suitable means, not shown, for separating the material from the flowing air stream. It is to be noted that a bearing 152 is fixed on the end wall of the fan housing 14-8 and rotatably receives and supports the outer end of the rotor shaft 40 whereby to improve the stability of the rotor.

The fan housing 148 is secured to the housing section 132 and it is to be noted that the section 132 is mounted so that it and thus the fan housing may be easily opened to provide access to the interior of the milling chamber. Referring particularly to FIGS. 8, 9 and 11, it is seen that the means for mounting the housing 132 includes a pair of parallel rods 154 and 156 axially slidably mounted in apertured lugs 158 and 160 respectively welded or otherwise secured to the housing 32. A vertical pin 162 has opposite reduced diameter end portions rotatably extending into bearing end portions 164 and 166 of the parallel rods. A cotter pin 163 or the like extends through the upper end of the pin 162 for limiting downward movement thereof. A sleeve 170 welded or otherwise secured to the housing 132 is pivotally supported by the pin 162. This enables the housing to be pivoted about the pins 162 to and from the closed position shown in the drawings. It will be noted that in order to permit the bearing 152 to be assembled over the end of the rotor shaft, the fan housing must be bodily moved axially, and this movement is permitted by the rods 154 and 156 which may be shifted between the solid and broken line positions shown in FIG. 9. Outward movement of the rods is limited by flange 172 and 174 respectively retained on reduced diameter end portions of the rods 154 and 156 by nut members 176 and 178. Several fastening means 180 are spaced around the periphery of the housing 32 for securing the housing 132 against the end of the housing 32. In the embodiment shown, each of these fastening means comprises a pair of lugs 182-484 on the housing 32 and having a pin 186 extending therebetween, and a latch. member 188 connected to the housing section 132 and adapted to interengage with the pin.

The material to be pulverized is directed by downwardly extending duct means 199 from the feeding means 26 to the inlet opening 36 of the milling chamber. An opening 192 at the upper end of the duct means is adjustably controlled by a door 194 which may be held in any desired adjusted position by suitable means such as a support arm 196. Thus, the effective size of the opening 192 may be changed so as to control the volume and rate of air orgas flow through the apparatus.

The pulverizing apparatus may be utilized for processing various materials such, for example, food products including sugar, various grains and many others. It is often desirable to obtain a finished product which includes two or more pulverized ingredients mixed together such as a cake mix which includes flour and various ingredients. Such ingredients cannot be readily mixed uniformly after they have been finely pulverized. Therefore, it is to be noted that the feeding means 26 is constructed so as to feed a plurality of ingredients simultaneously to the milling chamber so that the ingredients will be thoroughly and uniformly mixed with each other during the milling or' pulverizing process. Thus, as shown in FIGS. 1, 2, and 3, the feeding means is provided with a pair of hoppers 200 and 262 separated by a partition 204, which hoppers may be filled with different ingredients to be processed with or with the same ingredients if desired. Feed screws 206 and 208 extend through the bottoms of the hoppers and means 210 which provides separate passageways having outlet openings within the duct means 190. Portions of the feed screw rods extend rearwardly through tubes 21-2 and 214 and are driven in timed relationship by output gears of a transmission 216 having an input shaft 218. A sprocket 220 on the input shaft is driven by a chain 222 which extends from a sprocket, not shown, on an output shaft 224 of a variable speed reducer unit 226 which is driven by a motor uni-t generally designated by the numeral 228. It will be appreciated that by predetermining the rate at which the feed screws 206 and 208 are driven with respect to each other, the materials from the hoppers 200 and 202 are fed in predetermined proportions to the milling chamber.

In the embodiment shown, another ingredient hopper 230 having a feed screw 232 extending therethrough is disposed for directing another ingredient into the hopper 202 through an opening 234 in the end of the hopper 202. This enables an ingredient in the hopper 230 to be mixed with the ingredient in the hopper 202 before the ingredients are discharged into the duct 190. The feed screw 232 carries a sprocket 236 fixed on a rear extension thereof, which sprocket is driven by a chain 238 extending from another sprocket, not shown, on another output shaft 240 of the variable speed reducer unit 226.

As mentioned hereinabove, larger and heavier particles of the material being pulverized and passing through the milling chamber tend to gravitate under the influence of centrifugal force toward the outer periphery of the milling chamber. -In order to obtain a finished product having a more uniform and relatively small particle size, these larger particles are recirculated through the milling chamber. In accordance with another feature of the present invention, the apparatus is provided with means for accomplishing recirculating of the larger particles which means is relatively simple. More specifically, a circumferentially elongated slot 250 is provided in the cylindrical housing 132 in radial alignment with the mill plate 128. A conduit member 252 is mounted on the cylindrical housing 32 and provides a passageway 254 communicating with the slot 250 and also communicating with the duct means 190. It is to be noted that the construction is such that the larger or heavier particles forced radially by the mill plate 128 will be projected into the passageway 254, and the air or gas pressure at the opening 250 will be greater than the pressure in the duct means 1-19 so that fluid will circulate back to the duct 190 through the passageway 254 and carry the particles which have entered the passageway back to the duct means. In order to control the rate of fluid flow back through the passageway 254, adjustable gate means is provided for controlling the effective size of the slot or opening 250 as shown in FIG. 10. This gate means includes a plate 256 extending into the passageway 254 between opposed surfaces of the member 252 and the cylindrical housing 32, which plate has an elongated slot 258 for accommodating a screw 260. It will be appreciated that the plate 256 may be adjusted left or right as viewed in FIG. when the screw 260 is loosened, and the plate will be retained in any adjusted position when the screw is tightened.

The plate member 256 has an inner end portion 262 which is inclined radially inwardly of and against the direction of rotation of the mill plate 128 and is bifurcated so as to embrace a peripheral marginal portion of the mill plate, see FIG. 3. The inclined plate portion 262 thus acts as a bafiie for deflecting the larger particles through the opening 250 and into the passageway 254-. A shield member 264 is pivotally connected to the inclined plate portion 262 as at 266 and extends into a guide slot 268 in the cylindrical member 32 for preventing the pulverized material from clogging the space behind the depending batlle portion 262.

While the preferred embodiment of the present invention has been shown and described herein, it is obvious that many structural details may be changed without de- 6 parting from the spirit and scope of the appended claims.

The invention is claimed as follows:

1. A pulverizing apparatus of the type described comprising :means providing a milling chamber having an inlet adjacent one end and an axial outlet at its opposite end, rotor means supported for rotation in said chamber means for pulverizing material entering said inlet and imparting circular motion to said material so that larger particles tend to gravitate toward the periphery of said chamber means, means providing a lateral opening in said chamber means upstream from said axial outlet for receiving pulverized particles gravitating toward the periphery of the chamber means, means disposed within said chamber means and in the vicinity of the periphery thereof and of the rotor means for direct-ing portions of said particles into said opening, and passageway means continuously providing open communication between said lateral opening and said inlet for directing particles entering said lateral opening back to the inlet.

'2. A pulverizing apparatus, as defined in claim 1, which includes gate means adjustably partially traversing said lateral opening for controlling movement of particles through said opening and back to the inlet.

3. A pulverizing apparatus of the type described comprising means providing a substantially cylindrical milling chamber having an inlet adjacent one end and an axial outlet at its outer end, duct means -for supplying material to be pulverized to said inlet, rotor means supported for rotation in said chamber means for pulverizing material entering the inlet and imparting circular motion to the material so that larger particles thereof gravitate toward the periphery of said chamber means, said rotor means including a perforated mill plate, means providing a lateral opening in said chamber means upstream from said axial outlet and adjacent said mill plate for receiving pulverized particles gravitating toward the periphery of said chamber means, baflie means mounted adjacent said lateral opening and projecting into said milling chamber adjacent said mill plate for directing particles through said lateral opening, and passageway means continuously providing open communication between said lateral opening and said duct means for directing particles entering said lateral opening back to the inlet.

4. A pulverizing apparatus, as defined in claim 3, wherein said baflle means includes portions overlapping a marginal portion of said mill plate and extending along opposite sides of said mill plate.

5. A pulverizing apparatus, as defined in claim 4, wherein said baffie means extends from a plate member adjustably partially traversing said lateral opening, said bafiie means and said plate member combining to provide a gate for controlling the effective size of said lateral openmg.

6. A pulverizing apparatus as defined in claim 1, where in said passageway means curves upwardly from said lateral opening and then immediately downwardly toward said inlet.

7. A pulverizing apparatus, as defined in claim 1, wherein said means providing the milling chamber includes a generally conical section tapering from adjacent said lateral opening substantially to said axial outlet, and said rotor means includes a shaft extending substantially through said milling chamber and through said axial outlet and blade means on said shaft outwardly of said outlet for pulling air and the like along with pulverized mate rial through said chamber means and said axial outlet.

References Cited in the file of this patent UNITED STATES PATENTS 436,370 Morgan Sept. 16, 1890 580,909 Storer et al. Apr. 20, 1897 619,354 S'chutz Feb. 14, 1899 811,671 Simpson Feb. 6, 1906 (Other references on foliowing page) 7 UNITED STATES PATENTS Williams Q Apr. 23, 1907 Sturtevant Sept. 19, 1916 9 Daniel Dec. 16, 1924 Arnold May 19, 1925 Witz 2 Mar. 22, 1927 Shepheard Feb. 21, 1928 Ruprecht et al Apr. 30, 1929 McAliistar Aug. 20, 1929 1 Taylor Aug. 20, 1929 Hitchcock Jan. 21, 1930- ONeill June 17, 1930 Crites July 22, 1930 Wood Nov. 10, 1936 McGrane Mar. 16, 1943 Arnold Jan. 16, 1945 Agthe Apr. 23, 1946 Wiemer June 28, 1955 Pollman Apr. 15, 1958 Penaud et a1 Feb. 24, 1959 Andreas June 23, 1959 FOREIGN PATENTS Great Britain Feb. 14, 1899 Great Britain of 1913 Switzerland Dec. 16, 1925 

1. A PULVERIZING APPARATUS OF THE TYPE DESCRIBED COMPRISING MEANS PROVIDING A MILLING CHAMBER HAVING AN INLET ADJACENT ONE END AND AN AXIAL OUTLET AT ITS OPPOSITE END, ROTOR MEANS SUPPORTED FOR ROTATION IN SAID CHAMBER MEANS FOR PULVERIZING MATERIAL ENTERING SAID INLET AND IMPARTING CIRCULAR MOTION TO SAID MATERIAL SO THAT LARGER PARTICLES TEND TO GRAVITATE TOWARD THE PERIPHERY OF SAID CHAMBER MEANS, MEANS PROVIDING A LATERAL OPENING IN SAID CHAMBER MEANS UPSTREAM FROM SAID AXIAL OUTLET FOR RECEIVING PULVERIZED PARTICLES GRAVITATING TOWARD THE PERIPHERY OF THE CHAMBER MEANS, MEANS DISPOSED WITHIN SAID CHAMBER MEANS AND IN THE VICINITY OF THE PERIPHERY THEREOF AND OF THE ROTOR MEANS FOR DIRECTING PORTIONS OF SAID PARTICLES INTO SAID OPENING, AND PASSAGEWAY MEANS CONTINUOUSLY PROVIDING OPEN COMMUNICATION BETWEEN SAID LATERAL OPENING AND SAID INLET FOR DIRECTING PARTICLES ENTERING SAID LATERAL OPENING BACK TO THE INLET. 